No longer password dialog for encrypted VM

[mbee]

Host: Win10
Guest: encrypted Kubuntu.
VirtualBox: 7.0.12 r159484

Out of a sudden (today) no password dialog will be shown when resuming the machine. The "Restoring Virtual Machine" dialog finishs, the VM's background becomes unblurred, also the Mouse Cursor has changed yet to the one of the guest, but nothing is accessable. Last lines of the log (can provide more, if requested):

Code: Select all

00:00:19.580987 Changing the VM state from 'RESUMING' to 'RUNNING'
00:00:19.581003 Console: Machine state changed to 'Running'
00:00:19.919484 GUI: UIMachineViewNormal::adjustGuestScreenSize: Adjust guest-screen size if necessary
00:00:19.919707 GUI: HID LEDs sync is enabled
00:00:19.934587 GUI: UIMachineLogicNormal::sltCheckForRequestedVisualStateType: Requested-state=1, Machine-state=6

[mbee]

After a forced shutdown for the guest, everything was back to normal. But still... no idea if this could lead to a bricked VM.

[scottgus1]

Glad it's up and running again!

Out of a sudden (today) no password dialog will be shown when resuming the machine.

It would probably be better not using saved states or pauses or trusting the host to handle the VM when closing the lid or shutting down the host OS, especially with an encrypted VM. Shut the VM down using the VM OS's shut down commands ahead of time.

no idea if this could lead to a bricked VM.

Backups are a ubiquitous part of modern computing, and can handle such a problem in a VM. The VM should be completely shut down not save-stated, and the VM's folder containing the .vbox file and the disk file(s) should be copied regularly. See https://www.virtualbox.org/manual/ch09. ... encryption

Since the DEK is stored as part of the VM configuration file, it is important that the file is kept safe. Losing the DEK means that the data stored in the VM is lost irrecoverably. Having complete and up to date backups of all data related to the VM is the responsibility of the user.

[mbee]

or trusting the host to handle the VM when closing the lid or shutting down the host OS

This is not, what I do. I always save the VM from the respective dialog, appearing when clicking the cross on the upper-right corner of her enclosing VirtualBox window. So, the program has to handle this on its own.

It would probably be better not using saved states

So, you would recommend not to use state-saved machines at all? This sounds a bit strange to me in respect to some quite common use case. I used VMware Workstation for many years in this way (also encrypted machines). Also when using VirtualBox I create backups of the shutdown machines regularly.

[scottgus1]

So, you would recommend not to use state-saved machines at all?

Yes, especially with an encrypted VM. As Scotty said to Captain Kirk:

The more they overthink the plumbing, the easier it is to stop up the drain.

Saved States do not always guarantee a proper restart. Anything changes on the host - hardware, Virtualbox version, a bit flip - and the saved state environment may not match up correctly to allow a restart. Then you'd have to discard the saved state, and data loss would result.

The fact that it has worked for some time does not preclude a failure in the future a la gambler's fallacy. And the forum has a reasonable number of saved state failure posts in it. Nothing is perfect. Especially on commodity hardware.

Add in the encryption, and there's the extra point of concern that not only the unsaved data but the whole set of data is unrecoverable, and letting the VM balance on something that could come out from under it at any time becomes more concerning if the data is important.

Saved states were developed when hard drives were slow. My VMs on an SSD boot and shut down way faster than saving and restoring state. Saved state is good for when one fails to shut down the VM before shutting down the host (and hopefully the host allows time for the saved state to complete). But using it constantly is increasing the vulnerability front.

Good that you have backups, kudos for that!